1. Field of the Invention
The present invention relates to a pipe attaching structure of a fuel tank, which is provided with a pipe attachment member adapted to attach pipes to an exterior wall of the fuel tank composed of a synthetic resin.
2. Description of Related Art
Conventionally, tubular blow molded products such as fuel tanks for motor vehicles, etc. have been formed of metal. But, recently, the tubular blow molded products composed of a thermoplastic synthetic resin have been frequently used, because vehicles bodies are light-weight and free from rust, and readily formed into desired configurations.
In many cases, tubular fuel tanks composed of the thermoplastic synthetic resin have been produced with the blow molding method, because tubular bodies can be readily formed. With the blow molding method, a parison composed of a molten thermoplastic synthetic resin is extruded from a die head (not shown) into a cylindrical configuration, and air is blown into the parison while holding the parison with the mold, thereby producing the fuel tanks.
As shown in FIG. 2, pipe attachment members 10 adapted to attach pipes and various tubes have been provided in an exterior wall 12 of a fuel tank 14. The pipe attachment members 10 are formed of members separately from that of the exterior wall 12 of the fuel tank 14, and attached to the exterior wall 12 after molding of the fuel tank 14. In this case, it has been required to mold the pipe attachment members 10 separately, and attach the pipe attachment members 10 to the exterior wall 12 of the fuel tank 14. Consequently, these works take time and labor.
As shown in FIG. 1, an exterior wall 16 is molded by blowing a fuel tank 18, and at the same time, a pipe attachment member 20 is molded in a blowing mold 22 (see Japanese Unexamined Patent Application Publication No. 2012-162244, for example.). In this case, a core member 24 adapted to mold the pipe attachment member 20 is provided in the blowing mold 22, and a pipe attaching molding section adapted to mold the pipe attachment member 20 is provided in the core member 24. When blow molding, the parison is injected into the pipe attaching molding section adapted to mold the pipe attachment member 20 of the core member 24.
A gap in the pipe attaching molding section adapted to mold the pipe attachment member 20 is narrow so that the parison is insufficiently filled in a cylindrical or bellow-like tip end thereof, whereby the configuration of a tip end of the pipe attachment member 20 may be broken off.